Liquid Crystal Composition, Color Filter and Liquid Crystal Display Apparatus, and Method of Forming Phase Difference Layer

Abstract

An object of the invention is to provide a liquid crystal composition intended to be applied to the surface of a base material to form a phase difference layer, the liquid crystal composition being capable of forming a phase difference layer well indicating homeotropic orientation without the presence of an oriented film, even if the liquid crystal composition is directly applied to the base material surface, as well as a phase difference layer formed by the liquid crystal composition, a color filter and a liquid crystal display apparatus using the phase difference layer, and further a method of forming the phase difference layer. To a liquid crystal composition containing one kind or two or more kinds of crosslinking liquid crystal compounds is further added at least an amino-based silane coupling agent to prepare a liquid crystal composition. The liquid crystal composition is directly applied to the surface of a base material to orient the crosslinking liquid crystal compound on the base material surface in a direction perpendicular to the base material surface, and then the resulting material is crosslinking polymerized to form a phase difference layer.

Description

TECHNICAL FIELD[0001]The present invention relates to a liquid crystal composition, a color filter and liquid crystal display apparatus, with a phase difference layer, made of the liquid crystal composition, and a method of forming a phase difference layer.BACKGROUND ART[0002]Recently, liquid crystal display apparatuses have the large advantages of thin-type, small weights and low consumption of electric power, and thus are actively used for display apparatuses of personal computers, cellular phones, electronic organizers and the like. The liquid crystal display apparatuses utilize the birefringence of driving liquid crystals to perform switching of light. Thus, the liquid display apparatus has the problem of view angle dependency attributable to the birefringence of driving liquid crystals. For the resolution of the problem, a variety of phase difference layer forming films have been developed. The phase difference forming film is normally fabricated by stretching of film made of p...

AI Technical Summary

Benefits of technology

[0034]A phase difference layer forming method of the invention involves further adding an amino-based silane coupling agent to a liquid crystal composition containing a crosslinking liquid crystal compound, and then directly applying the resulting material to the top surface of a base material to form a coating film. Then, the method involves curing the crosslinking liquid crystal compound present in the coating film in a perpendicular oriented state to enable a phase difference layer that stably homeotropically orients to be provided. Thus, there is no need to form an oriented film on the top surface of a base material in advance. Moreover, according to the method of the invention, even when a phase difference layer is formed on the top surface of a base material such as a transparent substrate or a colored layer, a phase difference layer that stably homeotropically orients can be formed. In particular, even when the entire surface or a part of the colored layer surface is subjected to cleaning treatment and / or surface modification treatment in advance, use of the method of the invention prevents homeotropic orientation of a crosslinking liquid crystal compound constituting a phase difference layer from being disturbed.

[0035]A liquid crystal composition of the invention is formed by addition of a crosslinking liquid crystal compound and an amino-based silane coupling agent. This makes it possible to stably perpendicularly orient the crosslinking liquid crystal compound in the liquid crystal composition without the presence of an oriented film regardless of surface properties of the base material, when a liquid crystal composition of the invention is applied to the surface of, for example, a base material formed by a colored layer on a glass substrate to thereby form a coating film, and then a crosslinking liquid crystal compound present in the coating film is oriented and cured. In particular, even for the top surface of a base material of which surface properties are changed through cleaning treatment or surface modification treatment, the use of the liquid crystal composition of the invention enables the formation of a phase difference layer that stably homeostatically orients without disturbing the orientation of the crosslinking liquid crystal compound contained in the composition.

[0036]In addition, according to the present invention, inclusion of a ketimine-based silane coupling agent in a liquid crystal composition has the effect that a phase difference extremely excellent in transparency can be provided.

[0037]A color filter provided with a phase difference layer constituted by containing the above ketimine-based silane coupling agent is very high in transparency of a phase difference layer as described above, thereby achieving high contrast and being capable of providing a higher quality image.

[0038]The phase difference layer excellent in the orientation stability exhibits an excellent phase difference function and contributes to a view angle modification effect greatly. In other words, a color filter provided with the phase difference layer of the invention has no light leakage when the color filter is sandwiched between polarizing plates placed in a crossed Nicols state and observed under a polarization microscope. For this reason, the use of the color filter in a liquid crystal display apparatus can provide a high quality display. In particular, when a luminance ratio of the display of a liquid crystal cell using the color filter of the invention is measured and the luminance ratio is 1000 or more, the above liquid crystal cell can provide a very excellent display.

[0039]In particular, a color filter exhibiting a phase difference value of 4 nm or less of the invention preferably provides a particularly good homeotropic orientation.

Problems solved by technology

Thus, the liquid display apparatus has the problem of view angle dependency attributable to the birefringence of driving liquid crystals.

A refractive index of the adhesive applied to the substrate differs from that of a phase difference layer forming film, thereby posing a problem in that the former film causes irregular refraction on the surface of a display.

Furthermore, when the phase difference layer forming film is used, there is a problem of being incapable of carrying out patterning for a phase difference layer fit to the pixel size of a display, or a problem of a change of optical properties by time lapse shrinkage due to low heat resistance, or the like.

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